In the rear of the Court House stands the former County Prison, a substantial brick building, with granite trimmings. It is now used for temporary detention of prisoners at trial, and by agreement with the Commissioners the town of Plymouth leases a portion of the building for a police station.

In May, 1908, the County purchased a large farm at the south part of the town, and erected suitable buildings of cement concrete, and prisoners convicted of minor offences are there kept at work with the design of making the penal institution self-supporting, as well as contributing to the health and general welfare of offenders detained for short terms. The new prison is light, commodious and airy, and has 140 cells for men, and 12 for women. The number of prisoners averages about 120, about half of them being “trusties,” who perform the farm labor cheerfully, with but little oversight other than that necessary for direction. The prisoners were transferred from the old jail in the middle of July, 1911. Sheriff Earl P. Blake rules humanely but firmly, and is as popular with his criminal household as he is throughout the county. This rational employment of prison labor for self support, is working splendidly, and the farm, the first of the kind in this country to be established on such a basis, is visited with much interest by officials connected with the criminal institutions of this and other states for the purpose of learning the methods of administration.